Switching device



H. o. SIEGMUND Aug. 25, 1936.

SWITCHING DEVICE Filed Feb. 9, 1935 INVENTOE' H. 0. S/EGMUND A TTORNEV Patented Aug. 25, 1936 UNITED STATES PATENT OFFICE assignor to Bell Telep hone Laboratories, In-

corporated, New York, N. Y., a corporation of New York Application February 9, 1935, Serial No. 5,692

3 Claims.

This invention relates to switching devices and particularly to electromagnetic relays of the type extensively employed in telephone systems.

, One of the major diificulties encountered in the-operation of electrical circuits and particularly telephone circuits is the occasional abnormally high resistance introduced at the contacts of the switching devices. In the case of noble metal contacts, this resistance is due principally to the presence of foreign particles, such as dust, between the contacting members. Relay bases are ordinarily provided with apertures through which the terminal ends of the contact springs and windings extend for the purpose of making connection with the circuits controlled by the relay. These apertures permit access to the structure of foreign matter which eventually may find its way to the relay contacts.

It is the object of this invention to provide a covered relay structure which precludes the possibility of admission of dust or other foreign l matter into the relay from the terminal end thereof and thereby insure reliability of operation from a contact standpoint.

This object is attained in accordance with a feature of the invention by molding the relay contact springs into one or more molds which constitute a base-like support for the relay cover. This and other features of the invention will be readily understood from the following detailed description made with reference to the accompanying drawing in which,

Fig. 1 is a side elevation of a relay structure embodying the features of this invention in which the relay cover is broken away at one end to disclose the terminal end of the relay;

Fig. 2 is a fragmentary perspective of the terminal end of the relay;

Fig. 3 is an exploded view of the cooperating elements which constitute the terminal end of the relay;

Fig. 4 is a rear elevation of the structure shown in Fig. 2; and

Fig. 5 is a perspective view of a modified form of the relay terminal end.

The relay core I0, upon which a form wound coil II may be supported, may be welded to a yoke-piece I2 which, in turn, is welded to the cross-piece or end member I 3. The yoke-piece I2 as illustrated, is provided with an integral right angle projection I4, though the portion I4 may be an independent element secured to the back edge of the yoke I2 by welding in such a manner that its rear surface is in alignment with the back edge of cross-piece I3. Each of the three exposed edges of portion I4 is provided with a groove, such as I5 and I5- A for a purpose to be hereinafter described.

The relay contact springs and winding terminals are molded in a mold of insulating mate- 5 rial. As illustrated, the springs are molded together in pairs, though each spring may be molded separately without departing from the spirit of the present invention. As clearly shown in Figs. 2 and 3, each unit comprises a mold I6 10 with its respective springs I1 embedded therein, each mold being provided with a ridge I8 which fits into the groove I 5 on element I4 to provide an effective seal between the molds I6 and the element I4. Each mold is furnished with two cylin- 15 drical holes I9 which extend the entire depth of the mold and are adapted to be placed in alignment with corresponding holes in adjacent molds and with the holes 2I in cross-piece I3 after assembly as will appear presently. The holes I8 20 accommodate screws 20.

In assembling the terminal end of the relay structure, the molded spring units are built up one after the other on the cross-piece I3 so that their respective ridges I8 fit into the grooves I5 25 in the upper and lower edges of element I4. A clamping piece or end member 23 is placed across the uppermost units and the screws 20 passed through the countersunk holes 24, the mold holes I9 and the holes 2| in cross-piece I3. The holes 30 2| may be threaded to receive the screws 20 or they may be countersunk on the outer surface of cross-piece I3 to accommodate nuts into which the screws 20 may be threaded. On its inner surface the piece 23 is furnished with a ridge 35 34 which fits into the groove I5A to insure an effective seal between the elements 23 and I4. The structure after assembly, as illustrated in Fig. 2, provides a rigid rectangular cap-like support or seal over which a cover 25 is snugly 40 fitted. As shown in Fig. 4, the rear of the relay is completely sealed and eifectively shielded against dust or other foreign matter.

The holes 21 in the portion I4 accommodate screws 28 by virtue of which the relay may be 45 secured to a mounting frame 29 as shown in Fig. 1.

In the modification shown in Fig. 5, all the relay spring members are molded together in a single U-shaped mold 30 which replaces the individual molds I6 and the clamping piece 23 of 50 Figs. 2 and 3.

The relay armature has been omitted from the drawing in order not to complicate the disclosure. A cross-bar type armature, such as is disclosed in Patent 1,973,090, issued to D. D. Miller 55 relay shown. Such an armature is mounted on' the relay by means of the well-known reed type hingeand in the present invention a reed hinge associated with each longitudinal'leg of the armature would be interposed between the crosspiece l3 and the adjacent mold [6. In other words, the reed type hinge would constitute an elementin the assembly included between the elements l3 and 23 and would be located directly upon the surface of element l3.

What is claimed is:

1. In combination, a switching device, a cover for said device having an opening by way of which said device may be placed within said cover, and a seal for the opening in said cover, said seal comprising in part oppositely disposed rows of molds into which the contact springs of said switching device are embedded, and a pair of and members between which said rows of molds are located.

2. In combination, an electromagnetic switching device, a cover for said device having an opening by way'of which said device may be placed within said cover, and a seal for the opening in said cover, said seal comprising oppositely disposed rows of molds into which the contact springs of said switching device are embedded, a pair of end members between which said rows of molds are located, and a member centrally disposed with respect to said molds and said end members.

3. In combination, an electromagnetic switching device, a cover for said device having an opening by way of which said device may be placed within said cover, and a seal for the opening in said cover, said seal comprising oppositely disposed rows of molds into which the contact springs of said switching device are embedded, a pair of end members between which said rows of molds are clamped, and a member rigidly secured to one of said end members and centralh located with respect to said rows of molds and said end members and provided with a peripheral 20 groove into which ridges on said molds and v one of said end members fit to effect a dust-proof union of the several elements constituting said seal.

HUMPHREYS O. SIEGMUND. 

